Manchester — Republicans eyeing the 2016 White House race battered President Obama’s health care law and nicked each other Saturday, auditioning before a high-profile gathering of conservatives that some political veterans said marked the campaign’s unofficial start.

A speaking program packed with potential presidential candidates weighed in on the House Republicans’ controversial budget, the party’s struggle with Hispanics, the GOP’s future and the upcoming midterm elections while taking turns on a conference room stage facing hundreds of conservative activists gathered in New Hampshire’s largest city.

But the Republican Party’s near-universal opposition to the president’s health care law dominated the conversation just days after Secretary of Health and Human Services Kathleen Sebelius resigned after leading the rocky rollout of the program derided as “Obamacare.”

Texas Sen. Ted Cruz declared that one resignation is not enough. “We are going to repeal every single word of Obamacare,” said the first-term senator and Tea Party favorite.

Another Tea Party favorite, Kentucky Sen. Rand Paul, insisted that the GOP must broaden its appeal in order to grow. The Republican Party, he said, cannot be a party of “fat cats, rich people and Wall Street.”

Neither Paul nor Cruz defended the sweeping budget plan authored by another potential presidential contender, Rep. Paul Ryan, R-Wis. The budget, approved by the Republican-led House in recent days, transforms entitlement programs such as Medicare and Medicaid to help reduce federal spending.

Former Arkansas Gov. Mike Huckabee said the Ryan plan was simply “a starting point,” but that, “there would be some things I’d probably change,” declining to be more specific.

“His whole stance is to knock the hell out of Medicare, Medicaid and Social Security,” Trump said of Ryan. “I would leave it alone. I don’t want to hurt people.”

The summit comes as prospective presidential candidates begin to step up appearances in key states ahead of the 2016 presidential contest, even though New Hampshire’s first-in-the-nation presidential primary isn’t planned for another two years.

“It’s the unofficial kickoff of the 2016 process,” said Republican operative Mike Biundo, who managed Rick Santorum’s last presidential campaign.

As potential presidential candidates jockey for position, the stakes are high for the November’s midterm elections, where Republicans are fighting to claim the Senate majority. The president’s health care law could figure prominently in November House and Senate contests across the country.

Sebelius resigned on Friday, days after the Obama administration announced that enrollment in the Affordable Care Act had grown to 7.5 million, a figure that exceeded expectations and gave Democrats a surprise success after a disastrous rollout. It was welcome news for Democrats, who have been forced to defend their support for the unpopular law.

In a conference call, Rep. Chris Van Hollen, D-Md., insisted that “Democrats are not running away from the Affordable Care Act.”

Democratic National Committee spokesman Mike Czin noted that Republican opposition to the health care law was the foundation of the GOP’s unsuccessful political strategy in 2012. He said that the debate has changed now that the law has been implemented and millions of people are enjoying its benefits.

“That’s a debate that we’re going to have, and we’re eager to have,” Czin said.

At the same time, Van Hollen, the senior Democrat on the House Budget Committee, called for Republicans to defend their support for a GOP budget plan introduced last week that would repeal the health care law, transform Medicare, reintroduce the “doughnut hole” for prescription drug costs and enact deep cuts in education.

Trump, who says he’s also considering a Republican presidential bid, echoed many of the Democrats’ concerns. “Leave my Medicare alone,” he declared.

Campaigning in Iowa the night before, Ryan defended his recently passed budget plan as a sign of growing GOP unity.

“Some people wanted to go further, some people thought it went too far. The point is we unified around these common principles in a plan,” the Wisconsin congressman said after headlining an Iowa GOP dinner. “That’s very important to me — which is we can’t just oppose, we have to propose.”

Back in New Hampshire, conservatives also criticized another potential presidential contender who was not in attendance, former Florida Gov. Jeb Bush, who recently suggested that many immigrants enter the United States illegally because of love for their families.